Known hitch assemblies of similar design are reset to the working or transport position in three manners: by uncoupling the tractor from the hitch assembly and rehitching, manually and automatically. At present, of interest are only mechanized or automated hitch assemblies employing normally hydraulic systems for transferring the implement from the transport to working position and vice versa.
Most of such hitch assemblies include a transverse bar and an arcuate or curved beam connected to a support wheel. Because in the transport position the farm machines are hitched in tandem, the beams curved in the vertical plane make it possible to accommodate the farm machines thereunder. There are known hitch assemblies in which, for coupling farm machines of different spans, use is made of a telescoping brace connecting the curved beams. Position of the hitch beams is locked by the brace. Variations in the angle between the beams is attained by changing the length of the telescoping brace and locking the hitch assembly in a preset position.
It is noted, however, that hitch assemblies with the vertical arrangement of the curved beams are generally very bulky and therefore require much metal for their manufacture. Also, they are of complicated structure.
There are further known implement hitch assemblies in which the arcuate or curved beam assumes a horizontal position when the implement is hauled. One such hitch assembly comprises a U-shaped frame having post ends thereof pivotably connected to longitudinal beams having self-aligning wheels at the ends. The rear self-aligning wheels can be provided with means for locking them in the transport position of the implement.
However, this construction makes use of a large number of support wheels and has a width during transportation exceeding the width of any single machine in the ganged-up implement.
There are known hitch assemblies in which the arcuate beam can assume both horizontal and vertical positions. Such hitch assemblies are free of many disadvantages inherent in the aforedescribed prior art machines.
More specifically, there is known an implement hitch assembly comprising a transverse bar having mounted thereon a mechanism for setting the implement to the transport or working position, and an arcuate beam connected to a support wheel through a suspension having a vertical axis of rotation and fixed relative to the arcuate beam (cf., SU, A, 1,250,180). The mechanism for setting the arcuate beam to the transport or working position has the form of two pivotably interconnected swing arms. A drive mechanism is fashioned as a hydraulic cylinder rigidly affixed to the transverse beam. In order to lock the arcuate beam in the working position and set the rear machine of the implement in the desired position, a telescoping support in the form of a hydraulic cylinder with a catch is rigidly secured on the transverse bar. This implement hitch construction enables to considerably reduce the time required for setting the implement to the working or transport position. Another advantage is the low amount of metal consumed for its fabrication and efficient operation.
However, the support wheel of the arcuate beam is operated manually which is labour consuming and inconvenient.